1. Field of the Invention
The present invention relates to a method, test medium, and novel chromogenic compounds for quantitatively identifying and differentiating general coliforms and Escherichia coli.
2. Description of the Related Art
Currently, in microbiology, the presence of indicator organisms is widely used to determine the quality of various products. For example, in the analysis of water, food and dairy products, the presence of members of the "coliform" group as well as the presence of the bacterial species Escherichia coli are considered very significant quality indicators. Therefore, test methods to effectively identify and enumerate these bacterial types are needed, and there is a continuing search for better, more accurate and simpler test methods in this area.
Numerous methods for determining, identifying and enumerating coliforms and E. coli currently exist, with varying degrees of accuracy and facility. Some test methods only indicate the presence or absence (P/A) of the organisms while some methods attempt to quantify the organisms in the test materials. Following are some of the current methods.